In general, an automobile production process includes engine and transmission processes that completes a main body of an engine, a press process that forms an exterior shape of a car, a body process that completes a car body of a finished car by assembling and welding panels of each part of the car, a painting process for corrosion prevention and exterior treatment, and an assembly process that assembles interior and exterior parts into the finished car and finishes the assembly.
FIG. 1 is a view showing a general car assembly line. As shown in FIG. 1, a car assembly line has a transfer line provided along each process stage. On a rail installed along the transfer line, continuous transfer of the car body by a skid for car body transfer and reciprocating transfer of the car body by a hanger type of transfer device are performed in conjunction with each other, whereby a car body assembling process is performed as a continuous automation process.
For such a continuous automation process of the car body assembly, it is very important to stably operate a plurality of driving units (motors) necessary for operation of a plurality of skids for car body transfer and a plurality of hanger type transfer devices. The number of driving units used in a car body assembly plant varies depending on the size of the plant, but is about several hundred. Even when only one driving unit fails, the continuous automation process of the plant is stopped, resulting in enormous loss. When a downtime occurs due to a failure of the driving unit, it is expected to cause a business to incur significant losses in operating costs due to equipment downtime as well as in repair costs.
According to recent data from the Ministry of Employment and Labor and the Korea Occupational Safety & Health Agency, the number of victims of occupational accidents is about 100,000 per year, which is converted into a loss of 18 trillion won per year. In most factories and industrial sites, work overload causes mechanical failures, which leads to serious accidents such as fire, explosion, and leakage.
As a method for avoiding the cost of downtime due to such an unexpected failure of the driving unit equipment, it is urgent to introduce a predictive maintenance system. Although various efforts are already being undertaken in the name of predictive maintenance, development of higher-grade processes is required for more efficient predictive maintenance.
A conventional diagnosis technique of equipment such as a driving unit of an industrial facility includes vibration analysis, oil analysis, and the like. The oil analysis is a method of diagnosing equipment by analyzing the oil used in the equipment and checking the state of wear or deterioration, but is problematic in that accuracy is poor. The vibration analysis is a method of checking defects by detecting displacement and acceleration from vibration of each part of the equipment, but is problematic in that introduction cost is very high, and detect irregular fluctuation, fluctuation per second/per minute, and irregular vibration and fluctuation in vertical and horizontal directions are difficult to detect and real time measurement thereof are impossible.
Moreover, the vibration analysis is based on an expensive system with a basic cost of 200 to 300 million won for ten rotating machine sites. Since even one small plant usually requires hundreds of driving units, it costs billions of won and it is difficult to apply in the car body assembly plant. In addition, a professional engineer who can analyze FFT vibration analysis must be present all the time, which results in a labor cost problem.
The related art of the present invention is disclosed in Korean Patent Application Publication No. 2011-0072123 (published on Jun. 29, 2011)